since */*/*/

since */*/*/
UK [sɪns] / US adverb, conjunction, preposition

Since can be used in the following ways: - as a preposition (followed by a noun): Everything has changed so much since last spring. - as an adverb (without a following noun): She left home in 1993 and hasn't been seen since. - as a conjunction (connecting two clauses): Paul's had several different jobs since he left school. Since there's no more business, we can all go home. When since is used for talking about time, the verb in the main clause of the sentence is usually in the present perfect or past perfect tense: It hasn't rained since the end of July. He had been composing music since he was ten years old. Sometimes the present simple or past simple is used in the main clause: It's over twenty years since we last met.
1) starting at a particular point in the past and continuing until now or until another point in the past

I've known Joanna since she was born.

Turkey has been a republic since 1923.

It's over nine years since Scotland won a game against England.

I'd not seen her since she went to live in Oxford.

ever since:

Paul started sailing in 1986 and he's been doing it ever since.

Ever since I was at school, I've wanted to write.

a) at some time after a particular point in the past

Since arriving in New York, Thomas has had over 15 job interviews.

There have been many changes around here since I was a boy.

The accident was blamed on the pilot, who has since retired.

since then:

Last year the company was expanding, but since then things have got really tough.

b) before now, or before a particular point in the past
long since (= a long time ago):

The people who built the temple have long since vanished.

2) used when explaining why someone does something or why a situation exists

Since Barbara is no longer my wife, I'm no longer responsible for her debts.

I shall not be able to attend the meeting since I shall be on holiday with my family.

You should talk to Karen since she's the one responsible for authorizing payments.

since when?spoken used for showing that you are surprised or annoyed by what someone has said or done, because it does not seem right, fair, or sincere

Since when has it been against the rules to have a coffee break?

Since when have you ever been concerned about my feelings?

English dictionary. 2014.